Delivering a conduit into a heart wall to place a coronary vessel in communication with a heart chamber and removing tissue from the vessel or heart wall to facilitate such communication

ABSTRACT

Devices and methods for delivering conduits into the wall of a patient&#39;s heart to communicate a coronary vessel with a heart chamber. The devices are passed through the coronary vessel and the heart wall to place the conduit and establish a blood flow path between the vessel and the heart chamber. Additional devices and methods are provided for removing tissue from a coronary vessel or the heart wall to establish a flow path between the coronary vessel in communication with the heart chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/540,703, filed Sep. 29, 2006, and entitled “Delivering a Conduit intoa Heart Wall to Place a Coronary Vessel in Communication with a HeartChamber and Removing Tissue from the Vessel or Heart Wall to FacilitateSuch Communication,” which is a divisional of U.S. application Ser. No.10/441,257, filed May 19, 2003, now U.S. Pat. No. 7,214,234, andentitled “Delivering a Conduit into a Heart Wall to Place a CoronaryVessel in Communication with a Heart Chamber and Removing Tissue fromthe Vessel or Heart Wall to Facilitate Such Communication”, which is acontinuation of U.S. application Ser. No. 09/170,994, filed Oct. 13,1998, now U.S. Pat. No. 6,651,670, and entitled “Delivering a Conduitinto a Heart Wall to Place a Coronary Vessel in Communication with aHeart Chamber and Removing Tissue from the Vessel or Heart Wall toFacilitate Such Communication”, which is a continuation-in-part of U.S.application Ser. No. 09/023,492, filed Feb. 13, 1998, now abandoned, andentitled “Methods and Devices Providing Transmyocardial Blood Flow tothe Arterial Vascular System of the Heart,” the entire subject matter ofeach of the foregoing applications is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to treating heart disease, and more particularlysystems, devices and methods for reestablishing or improving blood flowto the myocardium.

2. Description of Related Art

Despite the considerable advances that have been realized in cardiologyand cardiovascular surgery, heart disease remains the leading cause ofdeath throughout much of the world. Coronary artery disease, orarteriosclerosis, is the single leading cause of death in the UnitedStates today. As a result, those in the cardiovascular field continuethe search for new and improved treatments.

Coronary artery disease is currently treated by interventionalprocedures such as percutaneous transluminal coronary angioplasty(PTCA), atherectomy and coronary stenting, as well as surgicalprocedures including coronary artery bypass grafting (CABG). The goal ofthese procedures is to reestablish or improve blood flow throughoccluded (or partially occluded) coronary arteries, which isaccomplished, for example, by enlarging the blood flow lumen of theartery or by forming a bypass that allows blood to circumvent theocclusion. What procedure(s) is used typically depends on the severityand location of the blockages. When successful, these procedures restoreblood flow to myocardial tissue that had not been sufficiently perfuseddue to the occlusion.

Technological and procedural advances have improved the results obtainedby the medical procedures now used to treat heart disease, and inparticular coronary artery disease. There is, however, still much roomfor improvement. For that reason there remains a need in the art for newand improved systems, devices and methods for treating heart diseasesuch as arteriosclerosis.

SUMMARY

In one embodiment, the invention provides a device for delivering aconduit into the wall of a patient's heart to place the conduit incommunication with a heart chamber. The device includes a supportmember, a conduit disposed on the support member, and a sheath overlyingat least a portion of the conduit. The sheath is moved to expose aportion of the conduit upon positioning the support member and conduitat a desired location within the wall of the heart.

In another embodiment, the invention provides a device for delivering aconduit to a selected location in the wall of a patient's heart to placethe conduit in communication with a heart chamber. The device includes asupport member, a conduit disposed on the support member, and apositioning member configured to engage tissue so as to place theconduit in a selected position within the heart wall. The positioningmember is disposed a predetermined distance from the conduit. Theposition of the conduit relative to the heart wall is determined by thelocation of the positioning member relative to the heart wall.

In another embodiment, the invention provides a device for delivering aconduit through the wall of a patient's heart and the wall of a coronaryvessel to communicate a heart chamber with the coronary vessel. Thedevice includes a support member configured for placement through thewall of a heart into a heart chamber, and an expandable conduit sizedand configured for placement in the heart wall so as to communicate theheart chamber with a coronary vessel. The conduit is supported on thesupport member in a collapsed orientation and moved to an expandedorientation by an expansion mechanism on the support member.

In yet another embodiment, the invention provides a method for placing aconduit in the wall of a patient's heart. The method includes providinga support member and a conduit, passing the support member and theconduit through a wall of a coronary vessel and through the wall of apatient's heart, positioning the conduit within the wall of the heart,and removing the support member and leaving the conduit in the wall ofthe heart.

In another embodiment, the invention provides a method for placing aconduit in the wall of a patient's heart at a selected position withrespect to the heart wall. The method includes providing a supportmember and a conduit, the support member having a positioning memberdisposed at a predetermined location with respect to the conduit. Thesupport member and conduit are passed through a wall of a coronaryvessel and through the wall of a patient's heart, and the positioningmember is located against tissue to place the conduit at a selectedlocation within the wall of the heart. The support member is removedleaving the conduit in the wall of the heart.

In still another embodiment, the invention provides a method for placingand expanding a conduit in the wall of a patient's heart. The methodincludes providing a support member and a conduit, the conduit beingsupported in a collapsed orientation and movable to an expandedorientation. The support member and the conduit are placed in the wallof a patient's heart, the conduit is expanded and the support member isremoved while leaving the conduit in the wall of the heart.

In yet another embodiment, the invention provides a device and methodfor forming a channel that extends at least partially through the wallof a patient's heart and communicates with a heart chamber. Thisembodiment includes a shaft and a tissue removal mechanism movablysupported on the shaft. The tissue removal mechanism including atissue-removing portion that is actuated to remove a section of tissuefrom a patient's heart to form a channel that extends at least partiallythrough the heart wall and communicates with a heart chamber. A conduitmay be placed in the channel to form a blood flow path or the channelitself may form the path.

In another embodiment, the invention provides a device and method forremoving a portion of the wall of a coronary vessel located adjacent thewall of a patient's heart. This embodiment includes a shaft and atissue-removing mechanism disposed at a predetermined distance withrespect to the shaft. The shaft is placed adjacent the wall of acoronary vessel and the tissue-removing mechanism is positioned againstthe wall of the coronary vessel. An actuator coupled to thetissue-removing mechanism is actuated to remove a portion of the wall ofthe coronary vessel without removing a substantial portion of the wallof the heart located adjacent the coronary vessel.

In another embodiment, the invention provides a device and method forforming a channel through at least a portion of the wall of a patient'sheart by utilizing electrical energy. This embodiment includes a shaftand an electrode disposed adjacent a distal end of the shaft. Theelectrode is adapted to apply electrical energy to tissue in order toablate the tissue and is coupled to a source of electrical energy,preferably RF (radiofrequency) energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the following detaileddescription of preferred embodiments thereof, taken in conjunction withthe accompanying drawing figures, wherein:

FIG. 1 is a schematic view of a patient prepared to undergo acardiovascular surgical procedure, the patient's heart being exposed viaa retractor positioned in a thoracotomy formed in the patient's chest;

FIG. 2 is a perspective view of the heart shown in FIG. 1, wherein aportion of the heart wall is broken away for clarity;

FIG. 2A is an enlarged view of a portion of FIG. 2;

FIG. 3 is a perspective view of a conduit placement device constructedaccording to one embodiment of the invention, wherein the deviceincludes a sheath shown in a forward position;

FIG. 4 is a longitudinal sectional view of the device shown in FIG. 3;

FIG. 5 is a perspective, exploded view of the device shown in FIG. 3;

FIGS. 6A-6C are elevation views, in section, sequentially illustratingthe use of the conduit placement device shown in FIG. 3 to place aconduit in the wall of a patient's heart, wherein FIG. 6C shows theconduit positioned in the heart wall;

FIG. 7 is a perspective view of a conduit placement device constructedaccording to another embodiment of the invention;

FIG. 8 is a longitudinal sectional view of the device shown in FIG. 7;

FIGS. 9A-9G are elevation views, in section, sequentially illustratingthe use of the conduit placement device shown in FIG. 7 to place aconduit in the wall of a patient's heart, wherein FIG. 9G shows theconduit positioned in the heart wall;

FIGS. 10A-10C are detailed elevation views, in section, illustrating thepositioning mechanism of the conduit placement device shown in FIG. 7being used to position a conduit in a heart wall, the viewscorresponding to FIGS. 9A-9C;

FIG. 11 is a perspective view of a conduit placement device constructedaccording to yet another embodiment of the invention;

FIG. 12 is a longitudinal sectional view of the device shown in FIG. 11;

FIGS. 13A-13F are elevation views, in section, sequentially illustratingthe use of the conduit placement device shown in FIG. 11 to place aconduit in the wall of a patient's heart, wherein FIG. 13F shows theconduit positioned in the heart wall;

FIG. 14 is an elevation view, in section, illustrating the positioningmechanism of an alternative conduit placement device being used toposition a conduit;

FIGS. 15A-15F are elevation views, in section, of a tissue removaldevice constructed according to one embodiment of the invention, whereinthe Figures sequentially illustrate the device being used to removetissue from the wall of a patient's heart;

FIGS. 16A-16D are elevation views, in section, of a tissue removaldevice constructed according to another embodiment of the invention,wherein the Figures sequentially illustrate the device being used toremove tissue from the wall of a coronary vessel;

FIG. 17 is a perspective view of a tissue removal device constructedaccording to yet another embodiment of the invention;

FIGS. 18A-18C are elevation views, in section, illustrating the tissueremoval device shown in FIG. 17 being used to remove tissue from thewall of a patient's heart;

FIG. 19 is a perspective view illustrating the conduit placement deviceshown in FIGS. 3-6A being used with a guide member positioned through acoronary vessel and a heart wall; and

FIG. 20 is a perspective view illustrating the tissue removal deviceshown in

FIGS. 17-18C being used with a guide member positioned through acoronary vessel and a heart wall.

DETAILED DESCRIPTION

The invention provides methods and devices for delivering a conduitthrough a coronary vessel and the wall of a patient's heart to place theconduit in communication with a heart chamber, as well as methods anddevices for removing tissue from a coronary vessel or the heart wall. Itshould be noted that, as used herein, coronary vessel refers to anyvessel in the vascular structure of the heart, including arterialstructures such as coronary arteries and septal perforators. Thus, itwill be understood that the LAD 30 illustrated in the Figures is but oneexample of a possible vessel that may be placed in communication with aheart chamber.

Similarly, in the preferred embodiments the coronary vessel is placed incommunication with a heart chamber that contains oxygenated blood, i.e.,blood containing some level of oxygen. In the illustrated embodimentsthe conduit is placed in communication with the left ventricle 12. Itwill be understood, however, that the methods and devices of theinvention may be used to place a conduit in communication with anysource of blood (arterial or venous), for example, another heart chambersuch as the left atrium, the aorta and pulmonary veins.

FIG. 1 schematically depicts a patient who has been prepared to undergoa cardiovascular surgical procedure. A thoracotomy T formed in thepatient's chest by making an incision between two ribs (not shown)provides access to the thoracic cavity. A retractor, such as the ribretractor R shown in FIG. 1, may be used to spread the ribs and increaseaccess to the heart H and great vessels. The retractor is preferably ofa type that in addition to spreading the sides of the incision along afirst plane, also raises one side of the incision with respect to theother side to increase the working space around the heart. Any suitableretractor may be used, for example, one of the commercially availablerib retractors currently used in minimally invasive cardiac surgery. Asshown in FIG. 1, the retractor R provides considerable access to thesurfaces of the heart H and great vessels including the aorta A. Theleft side of the heart as well as the left coronary artery LCA is easilyaccessible via the thoracotomy T (FIG. 1).

FIG. 2 is an anterior view of a heart 10 showing the left ventricle 12,right ventricle 14, right atrium 16, aorta 18, pulmonary trunk 20 andpulmonary veins 22. In FIG. 2 the heart 10 is in diastole, or therelaxed phase of the heart cycle, so the aortic valve 24 is shownclosed. The left coronary artery 26, including the circumflex branch 28and the left anterior descending branch (LAD) 30, is visible in thisview, as is the right coronary artery 32. The coronary arteries 26, 28,30, 32 run along the heart wall 34 and deliver oxygenated blood to thetissue comprising the heart wall (epicardium, myocardium andendocardium) while the coronary veins run alongside the arteries andreturn blood to the coronary sinus (not shown).

A blockage or occlusion 36 is shown in the LAD 30 and results in partialor complete obstruction of the artery lumen 42, a condition oftenreferred to as narrowing of the arteries. This results in inadequate orno blood flow to the heart wall tissue fed by the portion of the LAD 30that is downstream of the occlusion 36. FIGS. 2-2A show a portion of theheart wall 34 disposed between the left ventricle 12 and the LAD 30, aswell as the inner and outer walls 38, 40 of the LAD 30. The devices andmethods of the different embodiments of the invention are illustratedand described in connection with their use on the portion of the heart10 shown in FIG. 2A. It will be understood, however, that suchdescription is for explanatory purposes and exemplifies only oneapplication for the invention.

FIGS. 3-5 illustrate a conduit delivery device according to oneembodiment of the invention. The delivery device is indicated by thereference numeral 100 and includes a conduit support member 102, aconduit 104, a housing 106 and an actuator 108. The conduit supportmember 102 is configured to support the conduit 104. For example, theconduit support member 102 may be in the form of a shaft having a step112 which defines a recessed portion 114 that receives the conduit 104(FIGS. 4-5).

The conduit support member 102 is preferably fixed with respect to thehousing 106. This allows the position of the conduit 104 to becontrolled by controlling the position of the housing 106. As anexample, the conduit support member 102 could be attached to the housing106, or, as shown, the conduit support member 102 could be integrallyformed with and extend away from a rear portion 116 of the housing 106(FIG. 4).

This embodiment of the invention may include means for positioning theconduit at a desired location within the heart wall. For example, thedevice 100 may be provided with markings 118 to indicate the position ofthe conduit support member 102 and conduit 104 within the heart wall. Ofcourse, other means of indexing the position of the conduit could beused if desired. The conduit support member 102 preferably has adilating portion 120 at its distal end forward of the conduit 104 to aidin introducing the device 100.

According to this embodiment of the invention, the device 100 includes asheath that covers all or a part of the conduit 104 to protect tissueand/or the conduit during its delivery into the heart wall. In theillustrated construction, the device 100 includes a sheath 122 that issized to engage the exterior of the conduit 104 in a relatively tightfriction fit. The sheath 122 has a distal portion 124 disposed over theconduit 104 and a proximal portion 126 disposed within the housing 106.The distal sheath portion 124 preferably is tapered to aid in dilatingthe opening in the tissue. The proximal sheath portion 126 is preferablyenlarged and has a surface 128 that confronts a surface 130 of thehousing 106 to prevent the sheath from disengaging the housing. Thesheath portion 126 is essentially captured between the housing 106 andthe conduit support member 102.

If the conduit support member 102 is formed integrally with the housing106 as shown, the sheath 122 may be placed within the housing 106 priorto final assembly of the housing. For example, the housing 106 andconduit support member 102 could comprise two sections that are securedtogether after placing the conduit support member 102 therein.Alternatively, the conduit support member could be a separate componentplaced in the housing 106 and secured thereto. The housing 106 and theconduit support member 102 may be formed of any suitable material, forexample, metals such as stainless steel or titanium, polymers orcomposite materials.

The sheath 122 preferably comprises a sleeve formed of a material thatis relatively strong and flexible so as to engage the conduit 104 andretain it in position on the conduit support member 102. The sheath 122overlies the conduit 104 to minimize damage due to interaction betweenthe conduit and body tissue during introduction of the device into thepatient's heart. The sheath 122 snugly surrounds the conduit 104 but isformed of a material that permits the sheath to be retracted by beingforced over the conduit. For example, the sheath may be formed of anysuitable strong material that is relatively thin but strong, such aspolyimide or stainless steel.

The sheath 122 is retracted to expose the conduit 104 once the conduithas been properly located in the heart wall. The sheath 122 may beretracted manually by moving it in a proximal direction or, as in thepreferred embodiment, an actuator may be used to retract the sheath. Theillustrated actuator 108 comprises the enlarged portion 126 of thesheath 122 from which a post 132 projects, a spring 134 disposed betweenthe surface 128 of sheath 122 and the surface 130 of housing 106, and aslot 136 in the housing 106.

The actuator 108 allows the sheath 122 to be selectively moved to exposethe conduit 104. In FIG. 3, the sheath 122 is in its forward (or distal)position. The spring 134 is captured between the surfaces 128, 130 andbiases the sheath portion 126 in a proximal direction; however, due tothe post 132 being located in a transverse section 138 of the slot 136,the sheath 122 remains in its forward position. In order to retract thesheath, the post 132 is moved out of the slot section 138 which allowsthe spring 134 to force the sheath portion 126 in a proximal direction.This moves the entire sheath 122 in a proximal direction (to the rightin FIG. 4) and uncovers the conduit 104.

The conduit 104 is a tubular element formed of an implantable,substantially rigid material. Suitable materials include, for example,titanium or stainless steel. The illustrated conduit 104 has a pluralityof openings 140 passing through the conduit wall (FIG. 5). The openings140 form edges along the length of the conduit 104 that contact thetissue of the heart wall to aid in anchoring the conduit in position.The tissue of the heart wall engages these edges as well as the openings140 to permanently fix the conduit 104 in position.

In addition to the conduit support member 102 and the sheath 122, thedevice 100 preferably includes a dilator 142 (FIGS. 4-5) having asharpened end 144 with a dilating portion, and an enlarged end 146configured to be grasped to manipulate the dilator. The dilator 142 isinserted into the conduit support member 102 so that the end 144projects beyond the distal ends of the support member 102 and the sheath122. The end 144 is pushed through the tissue of the coronary vessel andthe heart wall to form an opening to receive the conduit 104.Alternatively, the distal end 120 of the conduit support member 102 mayinclude a sharpened edge and a dilating portion for forming an openingin the vessel and heart wall. It should be recognized that the dilator142 is optional and may be omitted or replaced with a needle or otherincising instrument. Further, instead of dilating an incision in thetissue, a channel may be formed in the heart wall and the vessel walland the conduit positioned in the channel.

FIGS. 6A-6C show one possible application for the conduit deliverydevice 100, namely, placing a conduit in the wall of a patient's heartso that the conduit communicates a coronary vessel with a heart chamber.Referring to FIG. 6A, the dilator 142 is positioned in the device 100 sothat the end 144 of the dilator extends slightly beyond the distal endof the conduit support member 102 and the sheath 122. Next, the device100, with the sheath 122 overlying the conduit 104, is passed throughthe walls 38, 40 of the LAD 30 and through the heart wall 34. The device100 is then moved to a desired position with respect to the heart wall,such as the position shown in FIG. 6A.

As mentioned above, this embodiment of the invention may include meansfor determining the position of the conduit 104 relative to the heartwall 34. The markings 118 on the sheath 122 are used to position thedevice 100 (and in particular the conduit support member 102) at thedesired location, i.e., the location that places the conduit 104 at adesired position in the heart wall 34. The markings 118 may be read withrespect to the outer wall 40 of the LAD 30 or the heart wall 34 in orderto position the conduit 104. For example, the most distal marking couldbe located a predetermined distance from the proximal end of the conduit104 so that the position of the conduit can be determined by noting theposition of this (or any other) marking.

It should be recognized that the markings 118 represent only one meansfor placing the conduit at a desired location; various alternativepositioning mechanisms may be used. In addition, while this embodimentcomprises markings on the sheath 122, it will be understood that themarkings (or other positioning mechanism) may be carried by anothercomponent of the device 100. Also, while in the illustrated embodimentthe device includes both a sheath for covering the conduit and apositioning mechanism for correctly positioning the conduit, it will beunderstood that delivery devices constructed according to thisembodiment of the invention may include only one of the sheath andpositioning mechanism.

The device 100 and dilator 142 are passed through the walls of the LAD30 and the heart wall 34 as shown in FIG. 6A. It may be desirable insome applications to support the wall of the coronary vessel whileintroducing the device in order to ensure passage through the true lumenof the coronary vessel. Access to the coronary vessel may be facilitatedby supporting the wall of the vessel by any of the devices and methodsdisclosed in co-pending, commonly owned application (attorney docket no.004), U.S. Application Ser. No. 09/172,098, filed on Oct. 13, 1998, nowabandoned, and entitled “Devices and Methods for Use in PerformingTransmyocardial Coronary Bypass,” the disclosure of which isincorporated herein by reference.

With the device positioned as shown in FIG. 6A, the actuator 108 is usedto retract the sheath 122 and expose the conduit 104, which results inthe device being oriented as shown in FIG. 6B. In this embodiment, theconduit 104 is positioned so that its respective ends project slightlyinto the lumen 42 of the LAD 30 and the left ventricle 12.Alternatively, the ends of the conduit 104 may be flush, respectively,with the surfaces of the LAD inner wall 38 and the heart wall 34. Ifplaced in proximity to an occlusion (such as occlusion 36) the end ofthe conduit 104 that is disposed in the artery may by flush with thesurface of the occlusion. After the conduit 104 has been positioned asshown in FIG. 6B, the dilator 142 and the device 100 are removed fromthe conduit 104. This leaves the conduit positioned as shown in FIG. 6C.

The conduit 104 communicates the lumen 42 of the LAD 30 with theinterior of the left ventricle 12. As a result, oxygenated blood flowsfrom the ventricle 12, through the conduit 104 and into the LAD lumen42. The conduit 104 is rigid enough to resist the compressive forcesexerted by the heart wall 34 when the heart 10 contracts during systole.The conduit 104 thus remains open during both the systolic and diastolicphases of the heart 10. As mentioned above, a distal end of the conduit104 (FIG. 6C) preferably extends a slight distance beyond theendocardial surface of the heart wall 34 into the left ventricle 12.This prevents or reduces the likelihood of tissue moving over the distalend of the conduit and reducing or blocking flow from the ventricle 12into the conduit. Also as mentioned above, a proximal end of the conduit104 preferably extends a slight distance beyond the inner wall 38 intothe lumen 42 of the LAD 30. This prevents or reduces the likelihood oftissue moving over the proximal end of the conduit and reducing orblocking flow from the conduit into the LAD 30. Nevertheless, as notedabove, the ends of the conduit may be positioned at various locationswith respect to the heart wall 34 and the LAD 30.

The dimensions of the device 100 may vary depending on the applicationor the user's preferences. For instance, if the device is to be used ina minimally invasive, laparoscopic-type procedure, then the device wouldhave a length sufficient to reach the heart through ports, as opposed toa shorter instrument designed to be used via a thoracotomy as shown orin an open surgical procedure. As an example, for the illustratedapplication, the overall length of the device 100 may be in the range offrom about 4 to 6 inches. The diameters of the components of the device100 are preferably as small as possible to minimize the size of theopening in the coronary vessel; however, the size of the device may bedictated to a certain extent by the specific size and configuration ofthe conduit. If used to place a conduit having a diameter within a rangeof from about 0.080 inch to about 0.120 inch and a wall thickness of0.005 inch or less, the conduit support member would have an outsidediameter sized slightly smaller than the inside diameter of the conduit,while the sheath would have an inside diameter slightly larger than theouter diameter of the conduit.

FIGS. 7-8, 9A-9D and 10A-10C illustrate a conduit delivery deviceconstructed according to another embodiment of the invention. Thedelivery device is indicated by the reference numeral 148 and has aconstruction that is basically the same as described above with respectto the previous embodiment. As such, like reference numerals are used todesignate like components of the devices. The conduit delivery device148, however, includes an alternative mechanism for positioning theconduit at a desired location in the heart wall.

In particular, as shown in FIGS. 7-8, the delivery device 148 includes apositioning mechanism 150 disposed adjacent the distal end of thedevice. The positioning mechanism 150 is preferably in the form of anexpandable member that may be introduced into the heart wall in acollapsed orientation and then expanded to an expanded orientation. Thesheath 122 preferably covers all or a major portion of the positioningmechanism 150. In the illustrated embodiment, the positioning mechanism150 includes a plurality of flexible struts 152 disposedcircumferentially around the distal end of the device. Each strut 152has one end 154 attached to the dilator 142 adjacent the end 144 of thedilator. An opposite end 156 of each strut 152 is attached to theconduit support member 102 adjacent the end 120 thereof. The struts maybe formed of any suitable flexible material, such as stainless steel ornitinol. The ends 154, 156 of the struts 152 may be attached to thedilator 142 and the conduit support member 102 by any suitable means,for example, welding, brazing, adhesive, or a one-piece constructioncould be used with the struts integrally formed as part of the dilatorand/or support member.

As shown in FIG. 9A, the device 148 is positioned through the coronaryvessel and the heart wall 34 by pushing the end 144 of the dilator 142through the tissue, the dilating portions 120, 124 of the conduitsupport member 102 and the sheath 122 helping to facilitate passage ofthe device through the tissue. The device 148 preferably extends intothe heart chamber (e.g., left ventricle 12) a sufficient distance toensure that positioning mechanism 150 is located within the chamber. Atthis point the positioning member 150 is ready to be expanded and usedto position the conduit 104.

Next, the sheath 122 is retracted to uncover the positioning mechanism150, and in particular the struts 152 thereof (unless the device isintroduced with the positioning mechanism 150 uncovered). The sheath 122may be retracted in one step to uncover both the positioning mechanism150 and the conduit 104. However, it is preferred to uncover the struts152 of the positioning mechanism 150 first and maintain the conduit 104covered until it has been placed in its final desired position, therebyavoiding moving the exposed conduit 104 against the tissue. Therefore,the preferred and illustrated positioning mechanism 150 is actuated intwo steps.

The first step retracts the sheath 122 to the position shown in FIG. 9Bin order to expose the struts 152 of positioning member 150. This isdone by moving the post 132 out of the slot section 138 and into theslot 136 to allow the spring 134 to force the sheath 122 in a proximaldirection (FIG. 7). In the illustrated embodiment, the slot 136 includesa second transverse section 158 which forms a stop for the post 132.Thus, the spring 134 drives the sheath 122 away from the distal end ofthe device until the post 132 is stopped by the slot section 158. Therelative dimensions of the device 148 are such that when the post 132has moved into the slot section 158, the sheath 122 has moved an amountsufficient to uncover all (or a portion of) the positioning mechanism150. This allows actuation of the positioning member 150 in order toexpand the struts 152. After this, the entire device 148 is movedproximally until the positioning member 150 engages the endocardialsurface of the heart wall 34, which results in the device being orientedas shown in FIG. 9C.

With the positioning mechanism 150 engaging the heart wall as shown inFIG. 9C, the conduit 104 is positioned so that its respective endsproject slightly into the lumen 42 of the LAD 30 and the left ventricle12. Alternatively, as explained above, the ends of the conduit 104 maybe flush with the LAD inner wall 38 and the heart wall 34, or, if placedin proximity to an occlusion 36, the end of the conduit 104 that isdisposed in the artery may by flush with the surface of the occlusion.After the device 148 has been positioned as shown in FIG. 9C, the sheath122 is further retracted to expose the conduit 104, as shown in FIG. 9D.

This step is performed by moving the post 132 out of the slot section158 and into an axially extending slot section 160, shown best in FIG.7. This results in the spring 134 driving the sheath 122 proximally touncover the conduit 104, as shown in FIG. 9D. It will be appreciatedthat the slot sections 136, 138, 158, 160 comprise only one possiblemeans for controlling retraction of the sheath 122. For example, insteadof using a transverse slot section as a stop for the post 132, analternative construction could use a single axial slot and one or moredetents that form stops for the post. The detents could be spring loadedsuch that the post 132 is prevented from moving past the detent untilthe detent is depressed. Other mechanisms, of course, could be used aswell.

From the position shown in FIG. 9D, the positioning mechanism 150 ismoved to its collapsed orientation in which the struts 152 are generallystraight, as shown in FIG. 9E. This collapsed, low profile orientationpermits the conduit support member 102 and the positioning mechanism 150to be removed through the conduit 104. FIG. 9F shows the device 148 inthe process of being removed through the conduit 104, while FIG. 9Gshows the conduit 104 positioned in the heart wall 34 after the devicehas been removed.

FIGS. 10A-10C are detailed views (in which the sheath 122 has beenomitted for clarity) showing the positioning mechanism 150 and themanner in which the mechanism places the conduit 104 in a desiredposition. The positioning mechanism 150 is actuated by moving the ends154, 156 of each strut 152 toward each other (to expand the mechanism)or away from each other (to collapse the mechanism). FIG. 10A shows themechanism 150 in its collapsed orientation wherein the struts extend ina generally linear direction between the conduit support member 102 andthe dilator 142. The device 148 is introduced in this collapsedorientation to minimize the size of the opening in the coronary vesseland the heart wall.

In order to expand the positioning mechanism 150, the dilator 142 ismoved proximally with respect to the conduit support member 102 and thehousing 106. In the illustrated embodiment, the dilator 142 is retractedby grasping the enlarged portion 146 with one hand while holding thehousing 106 in the other hand. This moves the ends 154, 156 of thestruts 152 toward each other which causes the struts to expand in aradially outward direction, as shown in FIG. 10B. At this point thepositioning mechanism 150 is expanded, however, the conduit 104 is notlocated in the desired position; rather, as shown in FIG. 10B, theconduit 104 extends too far into the left ventricle 12.

The positioning mechanism 150 is then used to position the conduit 104in the desired location in the heart wall by moving the entire device102A proximally until the struts 152 engage the heart wall 34, as shownin FIG. 10C. The predetermined distance between the mechanism 150 andthe conduit is used to determine proper placement, for example, thedistance separating the ends of the struts 152 and the distal(ventricle) end of the conduit 104 is selected so that the conduit is inthe desired position when the struts are engaged with the heart wall.After this, as explained above with respect to FIGS. 9A-9G, the device148 is removed leaving the conduit 104 in place.

It should be understood that alternative actuators may be used to movethe sheath 122. For example, the sheath 122 could be moved manually touncover the positioning mechanism 150 and the conduit 104. Also,alternative positioning mechanisms could be used, such as providing thesheath 122 with markings that indicate when the sheath has beenretracted an amount that uncovers the positioning mechanism 150 or theconduit 104, or a flashback lumen that indicates when the device hasentered the coronary vessel or heart chamber. Additionally, an actuatorcould be used to carry out the final positioning step of FIG. 10C bymoving the entire device 148 to engage the positioning mechanism 150with the heart wall.

Also, in the embodiment shown in FIGS. 7-10C, the dilator 142 forms partof the actuator in that it is attached to the ends 154 of thepositioning struts 152. As such, in this embodiment the dilator 142 isnot removed separately from the device 148. Nonetheless, it will beappreciated that a separate, removable dilator could be used, forexample, by providing an additional member to which the ends 154 of thepositioning struts 152 are attached. The member would then be movedrelative to the conduit support member 102 to expand or collapse thepositioning mechanism 150.

A conduit delivery device constructed according to yet anotherembodiment of the invention is shown in FIGS. 11, 12 and 13A-13F. Thedelivery device is indicated by the reference numeral 170 and, like theembodiment of FIGS. 7-10C, has a construction that is similar to theembodiment of FIGS. 3-6C. Accordingly, like reference numerals are usedto designate like components. The device 170, however, includes analternative mechanism for positioning the conduit at a desired locationin the heart wall, as well as an alternative conduit and conduit supportmember.

The delivery device 170 includes a conduit support member 172 and aconduit 174. According to this embodiment of the invention, the conduit174 is positioned in the heart wall and then expanded. This embodimentincludes an optional sheath 122 that may be used to cover the conduit174 during introduction into the heart wall for reasons discussed above.

The conduit 174 illustrated in FIGS. 11-12 is expandable and may be inthe form of an coronary stent 176 comprising a plurality of struts orfilaments 178 that move relative to each other as the stent expands orcollapses. The stent 176 may be formed of any suitable material such asstainless steel or titanium, and may include struts as shown or anyalternative expandable structure. The stent 176 can be self-expandingand constrained by the sheath 122, or the stent may be expanded by asuitable mechanism. In the illustrated embodiment, an expandablemechanism is carried by the conduit support member 102 and comprises aninflatable balloon 180 around which the stent 176 is disposed. Otherexpandable mechanisms, inflatable or not, could of course be used,

As shown in FIG. 12, the conduit support member 172 has a recess 182 inwhich the balloon 180 is mounted, the recess extending between oppositesurfaces 184, 186. The stent 176 is mounted on the balloon 180 and thesheath 122 overlies the stent. Also, as shown in FIG. 12, the distalportion of the conduit support member 172 is tapered at 188 to aid indilating the opening in the tissue to introduce the device 170. As inthe above embodiments, the dilator 142, conduit support member 172,and-sheath 122 are sized and configured to nest together tightly so asto minimize the outer profile of the device.

This embodiment of the invention, as exemplified by the illustrateddevice 172, includes an alternative conduit positioning mechanism 190.The mechanism 190 comprises a positioning member 192 in the form of atubular shaft disposed over a portion of the sheath 122. The positioningmember 192 has a proximal end 194 attached to the distal portion of thehousing 106, for example, by welding, brazing, adhesive, etc.Alternatively, the positioning member 192 could be formed as an integralextension of the housing 106. The distal end of the positioning member192 has a stop surface 196 that is configured to contact tissue to gaugethe position of the conduit 174.

FIGS. 13A-13F show one possible application for the device 100 placing aconduit in the wall of a patient's heart to communicate a coronaryvessel with a heart chamber. As above, the heart chamber preferablycontains oxygenated blood and, in the illustrated embodiments is theleft ventricle. Also as above, the conduit may be placed incommunication with any source of blood, for example, another heartchamber such as the left atrium, the aorta, pulmonary veins, etc.

Referring to FIG. 13A, the sharpened end 144 of the dilator 142 ispassed through the walls of the LAD 30 and the heart wall 34. The device170 is moved toward the heart wall 34 until the stop surface 196 of thepositioning member 192 contacts the LAD 30, as shown in FIG. 13B. Thedevice 170 is constructed and dimensioned so that when the surface 196contacts the outer wall 40 of the LAD 30 the stent 176 is in the desiredposition within the heart wall. For example, the stop surface 196 of thepositioning member 192 may be disposed a predetermined distance X fromthe proximal end of the stent 176, as shown in FIG. 13C. Therefore,locating the stop surface 196 of the positioning member 192 also locatesthe stent 176 in a desired position (e.g., with the conduit ends in thecoronary vessel and the heart chamber, as shown in FIG. 13C).

In this embodiment, the position of the stent 176 with respect to theheart wall is indexed by controlling the position of the member 192 withrespect to the heart wall 34. In FIGS. 13A-13F the wall of the LAD 30remains dilated or distended while the device 170 is passedtherethrough. As in the previous embodiment, the wall of the coronaryvessel may be supported in a dilated or distended condition by any ofthe devices and methods disclosed in the aforementioned application, thesubject matter of which has been incorporated by reference herein. Thepositioning member 192 is configured to properly position the stent 176when the member 192 contacts the wall of the coronary vessel withoutcollapsing the wall. Thus, when in the position shown in FIGS. 13B-13C,the positioning member 192 indicates to the user that the stent 176 isin position and ready to be expanded.

Alternatively, as exemplified in FIG. 14, the device 170 may include apositioning member 192A that uses a collapsed wall of the coronaryvessel in order to gauge proper placement of the conduit. As shown, thedevice 170 may be constructed so that the stent 176 (or other conduit)is properly positioned when the positioning member 192A engages thecollapsed LAD 30. The distance Y between the stop surface 196A of thepositioning member 192A and the stent 176 could again be used to controlpositioning so that the stent is in the desired position when the wallof the coronary vessel is collapsed.

Returning to FIGS. 13A-13F, when the positioning member 192 is locatedas shown in FIG. 13B the stent 176 is positioned so that its endsproject slightly into the lumen 42 of the LAD 30 and the left ventricle12. As in the previous embodiments, the ends of the stent 176 may beflush with the surfaces of the LAD wall 38 and the heart wall 34 (or anocclusion such as stenosis 36). From the position shown in FIG. 13B, thedilator 142 is removed from the conduit support member 172, as shown inFIG. 13C. Alternatively, the dilator 142 is not used and the distal endof the conduit support member 172 is formed with an incising/dilatingportion for forming an opening in the vessel and the heart wall.

The sheath 122 is then moved to expose the stent 176 which results inthe stent struts contacting the tissue of the heart wall 34 and theinner wall 38 of the LAD. The conduit support member 172 is preferablyheld in position while the sheath 122 is retracted to ensure that thestent 176 remains in proper position. After the sheath 122 has beenretracted, the balloon 180 (or other expandable structure) is no longerconstrained and may be inflated, as shown in FIG. 13D. The balloon 180is inflated to expand the stent 108 to its expanded orientation, asshown in FIG. 13E. A suitable source of pressurized fluid such as asyringe pump delivers fluid to the balloon 180 by a lumen (not shown)passing through the conduit support member 172.

The balloon 180 is preferably sized to expand the stent 176 to anorientation that provides the stent with maximum radial strength toresist collapsing. The struts of the expanded stent 176 engage thetissue to aid in fixing the stent in position. With the stent 176 inposition and expanded, the balloon 180 is deflated and the conduitsupport member 172 is removed, leaving the stent 176 positioned in theheart wall as shown in FIG. 3F. As in the previous embodiment, the stent176 communicates the LAD 30 with the interior of the left ventricle 12to allow oxygenated blood to flow from the ventricle through the stentand into the lumen of the LAD. The stent 176 is constructed to resistthe compressive forces exerted by the heart wall 34 during systole sothat the stent remains open during both the systole and diastole. Asmentioned above, the ends of the stent 176 preferably extend into theLAD 30 and the left ventricle 12 to reduce the likelihood of tissueoccluding the ends of the stent.

FIGS. 15A-15F depict another embodiment of the invention that providesdevices and methods for forming an opening through the tissue of a heartwall. The opening is formed to receive a conduit that forms a flow pathbetween a coronary vessel and a heart chamber; alternatively, theopening itself forms a flow path with no conduit being used.Accordingly, the delivery devices and methods described above withrespect to the previous embodiments may be used (without a dilator) toplace a conduit in a channel or opening formed according to thisembodiment. In addition, while the devices and methods according to thisembodiment are described and illustrated in connection with formingchannels in a heart wall to establish a flow path between a coronaryvessel and a heart chamber, it will be appreciated that the devices andmethods may be utilized in various other applications.

Turning now to FIG. 15A, a device for forming a channel through tissueis designated generally by the reference numeral 200 and includes ashaft 202 and a tissue removal mechanism 204. The shaft 202 has aproximal end 206 in the form of a hub with a side port 208 which may becoupled to a vacuum source (not shown) with a filter for use inaspirating tissue removed by the device 200. A dilator 210 is positionedin the shaft 202 and has an end 212 configured to incise and dilate aninitial opening in the tissue. The device 200 is passed through the wallof the LAD 30 and the heart wall 34 until the distal end of the deviceis located within the left ventricle 12, as shown in FIG. 15B.

The illustrated embodiment includes a tissue support mechanism forengaging and supporting the heart wall 34 during formation of thechannel by the tissue removal mechanism 204. A preferred supportmechanism comprises an expandable structure 214 that may be placed in acollapsed orientation (FIGS. 15A-15B) for introduction through thetissue. The expandable structure 214 may be constructed as shown in theFigures, or it may have a construction the same or similar to the tissueengaging instruments disclosed in the aforementioned application, thesubject matter of which has been incorporated by reference.

The expandable structure 214 includes a plurality of flexible elements216 that move away from each other as the mechanism expands. Each of theelements 216 has one end fixed to the dilator 210 and an opposite endfixed to the shaft 202 (the ends not being shown in the Figures). Thesupport mechanism is expanded by retracting the dilator 210 whileholding the shaft 202 in place. This moves the ends of the elements 216toward each other and expands the structure 214 as shown in FIG. 15C.The expandable structure 214 of the support mechanism thus operates in asimilar manner to the positioning mechanism 150 of the embodiment shownin FIGS. 11-15.

In order to form a channel in the tissue, the expandable structure 214is used to securely grasp the tissue during engagement by the tissueremoval mechanism 204. This is accomplished by moving the expandablestructure 214 into engagement with the endocardial surface of the heartwall 34 and retracting the heart wall as shown in FIG. 15C. With thedevice 200 in this position, the tissue removal mechanism 204 is movedalong the shaft 202 into engagement with the coronary vessel and theheart wall, as shown in FIG. 15D. As such, the support mechanism engagesthe heart wall and acts as a refractor during actuation of the tissueremoval mechanism.

The tissue removal mechanism 204 may take various forms and, in theillustrated embodiment, comprises a rotatable coring element 218 with acutting edge 220 configured to bore a channel 222 in the coronary vesseland the heart wall. It will be recognized that this aspect of theinvention may utilize a tissue removal mechanism that forms a channelwithout utilizing a cutting edge as in the illustrated embodiment.Suitable alternative tissue removal mechanisms may utilize lasers, RFablation devices, coring devices, drills, etc.

As the coring element 218 moves through the tissue of the heart wall 34the cutting edge 220 removes a core of tissue to form channel 222. Thetissue may simply move into the interior of the coring element 218 as itis cut for subsequent removal with the device. Alternatively, asmentioned above, the removed tissue may be aspirated through the deviceto a receptacle (not shown). The coring element 218 passes through thetissue and then contacts the struts 216 of the expandable structure 214of the tissue support mechanism, as shown in FIG. 15D. At this point,the channel 220 has been created and the device 200 may be removed,which is accomplished by collapsing the expandable structure 214 of thetissue-supporting mechanism, as shown in FIG. 15E. The device 200 isthen removed leaving the channel 220 passing through the coronary vesseland the heart wall, as shown in FIG. 15F.

The dimensions of the device 200 also will vary depending on theapplication, as well as the desired size of the channels formed in theheart wall. As above, the size of the device will depend on the intendeduse of the device, for example, whether the procedure is performed in aminimally invasive manner through ports, through a thoracotomy as shown,or via an open surgical procedure. Also, the device may be used in adifferent manner than depicted. For example, the device may be passedall or substantially all the way through the heart wall into thechamber, and then moved back through the wall in order to core achannel.

FIGS. 16A-16F depict another embodiment of the invention that providesdevices and methods for removing tissue. In its preferred form, thisembodiment is used to remove a portion of a body of tissue, for example,a portion of the wall of a coronary vessel. This may facilitate easierplacement of a conduit to form a flow path between a coronary vessel anda heart chamber, or it may be used as an initial step in forming achannel that forms such a flow path. In the illustrated embodiment, thedevice and method are used to remove a section of the inner wall of acoronary vessel in order to place conduit in the heart wall. The wallsof coronary vessels, and in particular coronary arteries, are fairlyresilient (compared to the tissue of the heart wall) and tend to resistpassage of an instrument therethrough. In addition, the tissue of theartery wall may tend to move over and occlude the opening of a conduit(or channel) that communicates with the coronary artery. Thus, thisembodiment is useful in forming a reliable opening through the wall of acoronary vessel.

FIG. 16A shows a preferred device constructed according to thisembodiment. The device is indicated generally by the reference numeral240 and includes a shaft 242 and a tissue removal mechanism 244. Thetissue removal mechanism 244 has a construction somewhat similar to theexpandable structure 214 of the tissue support mechanism shown in FIGS.15A-15F it is collapsed for introduction and then expanded in order toengage tissue. The illustrated tissue removal mechanism 244 utilizeselectrical energy, preferably RF energy, to ablate selected portions oftissue; however, it should be understood that this embodiment of theinvention may be practiced by removing tissue mechanically rather thanelectrically, for example, by cutting the tissue as shown in FIGS.15A-15F.

In use, as shown in FIG. 16A, the device 240 is introduced into thelumen 42 of the LAD 30 by passing a sharpened end 246 of the shaft 242through the outer wall 40 of the LAD. Alternatively, an incision may beformed in the wall of the LAD 30 and the device 240 passed therethrough,the end 246 of the shaft 242 being used simply to dilate the incision.The device 240 is moved through the lumen 42 of the LAD 30 until thetissue removal mechanism 244 contacts the inner wall 38 of the LAD, asshown in FIG. 16B. At this point the mechanism 244 is ready to beactuated.

The tissue removal mechanism 244 comprises a flexible sleeve 248 movabledisposed over the shaft 242. The sleeve 248 has a plurality of slits 250that define a plurality of flexible elements 252 which preferably extendcircumferentially around the device. The distal portion 254 of thesleeve 248 is fixed to the shaft 242 such that moving the sleeve towardthe end 246 of the shaft expands the mechanism 244 by forcing theflexible elements 252 radially outward. Thus, once the device 240 isplaced against the inner wall 38 of the LAD 30, as shown in FIG. 16B,the tissue removal mechanism 244 is actuated by moving the sleeve 248 ina distal direction while holding the shaft 242 stationary. This causesthe mechanism 244 to assume the expanded orientation shown in FIG. 16C.

The flexible elements 252 are provided with conductive elements 256formed of any suitable material capable of conducting electrical energy.The conductive elements 256 are electrically coupled to an RF powersource that may be in the form of a suitable generator (not shown). Withthe mechanism located as shown in FIG. 16C, the source of RF energy isactivated and current is fed to the conductive elements 252.

The conductive elements 252 are in contact with the tissue of the innerwall 38 of the LAD 30 so that the current ablates the tissue surroundingthe tissue removal mechanism 244. Upon completion of the ablationprocess, the energy source is deactivated, the tissue removal mechanism244 is returned to the collapsed orientation shown in FIG. 16B, and thedevice 240 is removed. This procedure removes a portion of the innerwall 38 of the LAD 30, as shown in FIG. 16D. While in the illustratedembodiment a portion of the wall 38 of the LAD 30 is removed along witha small portion of the heart wall 34, it will be appreciated that thisaspect of the invention may be used to remove a portion of the wall ofthe LAD only. In fact, a portion of the wall of the coronary vessel maybe removed along with none or any desired amount of the heart wall.Also, although an expandable tissue removal mechanism is preferred toallow formation of a relatively small opening in the outer wall of thecoronary vessel (FIG. 16D), a non-expandable, tissue removal mechanismcould be used instead.

The embodiment of the invention shown in FIGS. 16A-16D may be used toform an opening through the inner wall of a coronary artery such as thatshown in FIG. 16D. A benefit of using electrical energy to remove thetissue (rather than mechanical removal) is that scar tissue forms alongthe periphery of the opening in the wall of the artery. The scar tissue,which is visible in FIG. 16D, maintains the opening in the artery walland minimizes the risk of tissue moving or growing over or into the endof the conduit positioned in the coronary vessel.

As with the previous embodiment, the dimensions of the device 240 willvary depending on the specific application and the amount and size oftissue to be removed. As an example, the device 240 may be used toremove a portion of the wall of a coronary artery that is approximately1-4 mm in diameter. Further, the device may be used in a differentmanner than depicted. For example, the device may be passed all orsubstantially all the way through the heart wall into the chamber, andthen moved back a small amount and actuated to remove a section of theendocardial portion of the heart wall. The device would then be movedthrough the heart wall until the tissue removal mechanism is locatedadjacent the inner wall of the coronary vessel, at which point thedevice is actuated to remove a section of the vessel wall.

FIGS. 17-18C depict another embodiment of the invention that providesdevices and methods for establishing an opening through body tissue, theopening preferably defined by a channel formed by electrical energy.This embodiment, in its preferred form, produces an opening defined bysurfaces of scar tissue that serve to maintain a patent channel. Thedevices and methods of this embodiment are preferably used to form achannel through a heart wall that communicates a coronary vessel with aheart chamber.

The illustrated embodiment comprises a channel-forming device indicatedgenerally by the reference numeral 280 in FIG. 17. The device 280includes a wire electrode 282 formed of a suitable conductive materialsuch as stainless steel. The electrode 282 has a proximal end 284configured to be attached to a conventional electrocautery instrument286 (shown in phantom). The electrode 282 is preferably disposable andtherefore is removably attached to the electrocautery instrument 286,for example, by a threaded connection, press fit, etc. The proximal end284 of the electrode 282 receives electrical energy from the instrument286.

A portion of the electrode 282 is preferably coated with an insulatingmaterial 288 so as to leave only the distal portion 290 of the electrodeexposed to contact and ablate tissue. The material 288 may be anyinsulator, for example, polyimide or graphite. As such, the distalportion 290 of the electrode 282 is used to ablate tissue while theremaining portion of the electrode is free to contact tissue withoutablating or damaging that tissue.

The dimensions of the channel-forming device 280 may vary depending onthe application and the size of the channels to be formed in the tissue.As an example, the proximal end 284 of the electrode 282 may be sizedand configured to engage a standard electrocautery pencil, for example,by having an outer diameter of approximately 0.095 inch. The shaft 282may comprise a wire having an outside diameter of approximately 0.015inch, while the insulating material 288 has an inside diameter ofapproximately 0.015 and an outside diameter of approximately 0.025 inch.

Referring to FIGS. 18A-18C, an exemplary application of this embodimentof the invention will be described. The channel-forming device 280 isplaced through the wall of a coronary vessel such as the LAD 30 shown inFIG. 18A. The distal end of the electrode 282 may simply be passedthrough the wall 40 of the LAD 30 or, alternatively, an opening can beformed in the artery wall and the device introduced through the opening.Once in the position of FIG. 18B, the RF power source is activated andcurrent is conducted through the electrode 182. The exposed portion 290of the electrode is moved into contact with the tissue of the wall 38 ofthe LAD 30 and then the tissue of the heart wall 34. The electrode 282is pushed through the tissue with a relatively small amount of force andthe RF energy ablates the tissue as it is moved. The particular amountof energy used may vary, as may the speed and force with which theelectrode 282 is moved through the tissue. These variables may becontrolled or adjusted to achieve the desired channel size andconfiguration. As an example, the device 280 may be supplied with 10watts of energy with the electrocautery instrument in pure cut mode.

Once the device 280 has been passed through the heart wall 34 asufficient distance to form a channel 292 passing therethrough, thedevice is removed as shown in FIG. 18C and the opening in the wall 40 ofthe LAD 30 is repaired. As shown, and as explained above with respect tothe embodiment of FIGS. 16A-16D, the ablation of the tissue forms alayer of scar tissue 294 that surrounds the channel 292 and aids inmaintaining the channel open over time. Also, while the illustratedembodiment forms a channel passing entirely through the artery wall 38and the heart wall 34, this aspect of the invention may be used to forma channel that extends only partially through one or both of theserespective tissue walls. As explained above with respect the previousembodiments, the dimensions of the device 280 will vary depending on theapplication and the size of the channel to be formed; for example, thedevice may be used to form a channel having an approximate diameter inthe range of from about 0.100 inch and about 0.200 inch.

FIGS. 19 and 20 show alternative embodiments of the invention wherein aguide member is used to introduce a conduit delivery device and a tissueremoval device, respectively. FIG. 19 shows a guide member G, which maybe in the form of a guide wire, and a conduit delivery device 100Ahaving a similar construction as the device 100 illustrated in FIGS.3-6C. The guide member G passes through the coronary vessel (LAD 30) andthe heart wall 34. The device 100A has a central bore, for example,through the dilator 142A, which allows the device to be passed over theguide member G. Thus, this embodiment utilizes a guide member to aid inpassing the delivery device through the coronary vessel and the heartwall into the heart chamber, the device being then being used to place aconduit in the heart wall as described above.

Similarly, FIG. 20 shows another alternative embodiment of the inventionincluding a guide member G which may be in the form of a guide wire, anda tissue removal device 280A constructed in a similar manner as thedevice 280 illustrated in FIGS. 17-18C. As above, the guide member Gpasses through the coronary vessel and the heart wall and is used toplace the device 280A in the heart wall. The tissue removal device 280Ahas a central bore that receives the guide member to place the devicethrough the coronary vessel and the heart wall into the heart chamber.The device 280 is then used as described above to form a channel in theheart wall.

It will be understood that the embodiments shown in FIGS. 19-20 are onlyexemplary in that any medical device configured to carry out a medicalprocedure may be introduced using a guide member placed through thecoronary vessel and the heart wall, the conduit delivery and tissueremoval devices disclosed herein being exemplary. Further, it should berecognized that the guide member may be placed through the coronaryvessel and the heart wall by any suitable method and system, and thatthe devices may be pushed over the guide member or secured thereto andpulled into the heart chamber. For example, the guide member may beplaced and used as disclosed in co-pending, commonly owned application(attorney docket no. 002), U.S. application Ser. No. 09/170,793, filedon Oct. 13, 1998, now U.S. Pat. No. 6,808,498, and entitled “Placing aGuide Member into a Heart Chamber Through a Coronary Vessel andDelivering Devices for Placing the Coronary Vessel in Communication withthe Heart Chamber,” the disclosure of which is incorporated herein byreference.

It should be noted that, as used herein, the term conduit refers to anystructure that is capable of conveying fluid from one point to another,for example, a tubular element with two or more open ends. In view ofthe fact that various characteristics of the conduit, for example, size,shape and surface configuration, may vary depending on the application,it will be recognized that the conduits in the illustrated embodimentsare merely exemplary. For instance, the conduit could be a rigid orflexible tubular element with solid or perforated walls, the conduitcould be straight over its length with the ends aligned or the endscould be offset, the exterior surface of the conduit may be treated toenhance fixation of the conduit in the heart wall, and the conduit mayor may not include a valve or other flow controlling mechanism.

It should also be noted that the various aspects of the inventionincorporated in the illustrated embodiments may be used together orseparately. For instance, a sheath and a positioning member constructedaccording to the invention can take different forms and may be usedwithout each and with any type of conduit. Likewise, the methodsdisclosed herein may be modified without departing from the principlesof the invention. For example, the methods may be carried out bycombining particular steps or varying the sequence of steps.

It will be understood that the invention encompasses. many variations ofthe preferred systems and methods described in detail herein. Forexample, the surgical approach depicted in FIG. 1 is but one exemplarymanner of accessing the heart in order to utilize the systems, devicesand methods of the invention. The approach illustrated in FIG. 1, whichcan be characterized as minimally invasive in that a thoracotomy is usedas opposed to a median sternotomy, may be desirable in someapplications. However, those skilled in the art will recognize thatother approaches may be used to access the heart in order to practicethe invention.

For example, an open surgical procedure including a median sternotomymay be used, or a minimally invasive procedure utilizing one or morerelatively small access openings or ports may be used. Endoscopes orthoracoscopes may be used for visualization if the procedure is trulyminimally invasive. Additionally, rather than forming one or moreincisions in the patient's chest wall, an endovascular approach may beused to guide various inventive devices to the heart through thepatient's vascular system to the heart, for example, by introducing thedevices into a peripheral vessel such as the femoral artery. If asurgical approach is used, the device may penetrate the outer and innerwalls of the coronary vessel and then the heart wall, or a cut-down canbe formed in the outer wall and the device passed into the vessel lumenand through the inner wall and the heart wall.

Further, the exemplary embodiments are described primarily in connectionwith their use in a beating heart procedure. Nevertheless, it will berecognized that the systems, devices and methods of the invention may beused in stopped-heart procedures utilizing cardiopulmonary bypass (CPB),or procedures during which the heart is intermittently stopped andstarted. For example, a conduit or channel formed according to theinvention may be used to deliver various pharmaceutical substances, suchas angiogenic growth factors or other substances that aid in theperfusion of surrounding myocardial tissue. As a result, the detaileddescription of preferred embodiments set forth in the drawing Figuresand accompanying disclosure should not be construed as limiting theapplications for which the invention may find utility.

The preferred embodiments of the invention are described above in detailfor the purpose of setting forth a complete disclosure and for sake ofexplanation and clarity. It will be readily understood that the scope ofthe invention defined by the appended claims will encompass numerouschanges and modifications to the embodiments disclosed herein.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present disclosure.

1. A device for delivering a conduit into the wall of a patient's heartto place the conduit in communication with a heart chamber, the devicecomprising: a support member having a length, a proximal end and adistal end; a conduit supported by the support member; a sheathoverlying at least a portion of the conduit, the sheath being movable toselectively expose the portion of the conduit covered by the sheath,wherein the sheath is moved to expose said portion of the conduit uponpositioning the support member and conduit at a desired location withinthe wall of the heart; and a positioning member that provides a visualindication of the position of the conduit with respect to the heartwall, wherein the positioning member is configured to engage a tissuesurface and is supported adjacent the distal end of the shaft, thepositioning member being movable between collapsed and expandedorientations.
 2. The device of claim 1, wherein the positioning memberis configured to engage a surface of the heart wall and is supported bythe sheath.
 3. The device of claim 2, wherein the sheath has a largediameter section that comprises the positioning member.
 4. The device ofclaim 1, wherein the conduit comprises an expandable tubular element andthe sheath comprises a retractable sleeve that overlies the tubularelement.
 5. The device of claim 4, wherein the expandable tubularelement comprises a stent and the support member comprises a shaft onwhich the stent is mounted, and the shaft includes an expansionmechanism for expanding the stent.
 6. A device for delivering a conduitthrough the wall of a patient's heart and the wall of a coronary vesselto communicate a heart chamber with the coronary vessel, the devicecomprising: a support member configured for placement through the wallof a hear so that a portion of the support member extends into a heartchamber; an expandable conduit sized and configured for placement in theheart wall so as to communicate the heart chamber with a coronaryvessel, wherein the conduit is supported on the support member in acollapsed orientation and is expanded to an expanded orientation forplacement in the heart wall; and wherein the support member has anexpansion mechanism that engages the conduit and is actuated to move theconduit from the collapsed orientation to the expanded orientation tosecurely position the conduit in the heart wall.
 7. The device of claim6, wherein the distal end of the support member is sharpened for formingan opening in the wall of the heart, and the support member has asection that is tapered for dilating the opening formed by the distalend.
 8. The device of claim 6, wherein the support member comprises ahollow member that removably receives a dilator having a sharpened tipfor forming an opening in the heart wall.
 9. The device of claim 6,further comprising a positioning member for engaging tissue to controlthe position of the conduit with respect to the heart wall.
 10. Thedevice of claim 9, further comprising a sheath disposed over the conduitso as to substantially cover the exterior of the conduit.
 11. The deviceof claim 10, wherein the sheath is a retractable sleeve and thepositioning member is supported by the sheath.
 12. A method for placingand expanding a conduit in the wall of a patient's heart, the methodcomprising steps of: (a) providing a support member and a conduit, theconduit being supported in a collapsed orientation and movable to anexpanded orientation; (b) placing the support member and the conduit ina wall of a patient's heart; (c) positioning the conduit within the wallof the heart; (d) expanding the conduit to the expanded orientation; and(e) removing the support member and leaving the conduit in the wall ofthe heart.
 13. The method of claim 12, wherein the conduit is passedthrough a wall of a coronary vessel and through the wall of the heartinto a heart chamber containing oxygenated blood, the conduit placingthe heart chamber in communication with the interior of the coronaryvessel.
 14. The method of claim 13, wherein the coronary vessel is acoronary artery and the heart chamber is the left ventricle.
 15. Themethod of claim 13, wherein the conduit is positioned in the wall of theheart so that one end of the conduit extends partially into the heartchamber.
 16. The method of claim 12, further comprising a positioningmember for engaging the heart wall to control the position of theconduit with respect to the heart wall.